Chromatid

Diagram of a duplicated and condensed metaphase eukaryotic chromosome.
(1) Chromatid – one of the two parts of the chromosome after duplication.
(2) Centromere – the point where the two chromatids touch.
(3) Short arm. (4) Long arm.

Chromatids are the daughter strands of a duplicated chromosome which are joined by a single centromere. When the centromere divides, the chromatids become separate chromosomes.[1]

Each of the two daughter chromatids contains the same DNA and chromatinprotein as its original chromosome. But in meiosis, crossing over (exchanges) take place between two of the non-sister chromatids. This has profound consequences: it produces genetic recombination, and increases the variability of gametes.